Synergistic mixtures of 1,2-alkane diols

ABSTRACT

The use of mixtures of two, three or more straight-chain 1,2-alkanediols, the chains lengths of which (i) are different and (ii) in each case are in the range of 5 to 10 C atoms, as antimicrobial active compounds is described. Compared with the pure 1,2-alkanediols, the mixtures have a synergistically intensified action.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of antimicrobial activecompounds and in particular antimicrobial active compounds in which anon-branched (straight-chain) 1,2-alkanediol is present in anantimicrobially effective amount.

2. Description of the Related Art

In the cosmetic and pharmaceutical industry and also in the foodindustry there is an ongoing need for agents with antimicrobialproperties, in particular for the preservation of products that areotherwise perishable (such as, for example, cosmetics, pharmaceuticalproducts or foods), but also for the direct cosmetic or therapeutictreatment of microorganisms which can have an adverse influence on thehuman or animal body. Microorganisms that can give rise to body odour,acne, mycoses or the like may be mentioned by way of example.

It is true that a multiplicity of antimicrobial active compounds arealready used in the technical fields concerned, but alternativescontinue to be sought in order to be able to carry out targeted specialtreatments and/or reduce side effects. However, in this context whensearching for alternative agents having an antimicrobial and inparticular a preservative action it must be taken into account that thesubstances used in the cosmetic, pharmaceutical and/or food sector mustbe

-   -   toxicologically acceptable,    -   well tolerated by the skin,    -   stable (especially in the customary cosmetic and/or        pharmaceutical formulations),    -   substantially and preferably completely odourless and    -   able to be prepared inexpensively (i.e. using standard methods        and/or starting from standard precursors).

The search for suitable (active) substances that possess one or more ofthe said properties to an adequate extent is made more difficult forthose skilled in the art because there is no clear dependence betweenthe chemical structure of a substance, on the one hand, and itsbiological activity towards specific microorganisms (germs) and itsstability, on the other hand. Furthermore, there is no predictablerelationship between the antimicrobial action, toxicologicalacceptability, tolerance by the skin and the stability of a substance.

SUMMARY OF THE INVENTION

According to a first aspect, the invention relates to mixtures of two,three or more straight-chain 1,2-alkanediols, the chain lengths of which(i) are different and (ii) in each case are in the range of 5 to 10C-atoms. In this context the proportions of the said diols in themixture are preferably set such that their antimicrobial action issynergistically intensified. The said 1,2-alkanediols include, inparticular, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and1,2-decanediol. In addition to the said 1,2-alkanediol mixtures, further(for example conventional) antimicrobial active compounds can bepresent, some of which—as explained further below—are able to develop afurther synergistic action.

The invention is based on the surprising finding that straight-chain1,2-alkanediols with a chain length in the range of 5 to 10 C atomsexhibit a synergistically intensified antimicrobial effect, at leastagainst selected germs, if they are combined with a second or furtherstraight-chain 1,2-alkanediols with chain lengths in the same range, thechain lengths of the first and the second and of the furtherstraight-chain 1,2-alkanediols being different, however.

In particular, it has been found that the mixtures according to theinvention of two, three or more straight-chain 1,2-alkanediols ofdifferent chain lengths are outstandingly suitable for use for thepreservation of articles that would otherwise be perishable (see above).

Should a person skilled in the art wish to use a mixture of, forexample, two straight-chain 1,2-alkanediols, the chain lengths of which(i) are different and (ii) in each case are in the range of 5 to 10 Catoms, for the antimicrobial treatment of a surface (for example of ahuman or animal body) or for the preservation of an article that wouldotherwise be perishable (for example of a cosmetic or pharmaceuticalformulation), he can select a particularly suitable pairing from allconceivable pairings in the following way:

-   1. Determination of the straight-chain 1,2-alkanediol with a chain    length in the range of 5 to 10 C atoms that has the strongest    individual action.-   2. Combination of the 1,2-alkanediol with the strongest individual    action with each of the other straight-chain 1,2-alkanediol having a    chain length in the range of 5 to 10 C atoms.-   3. Determination of that combination according to 2 which has the    strongest antimicrobial action.

Using the procedure outlined above, the person skilled in the art willas a rule arrive at the most effective, but always at a very good,combination of 1,2-alkanediols in the said chain length range. It ispointed out that although the alkanediol mixtures according to theinvention in some cases possess a synergistically increasedantimicrobial action against certain germs, against other germs,however, they only have an action that corresponds to the sum of theindividual actions or is even antagonistically impaired.

Although experts in the field had already concerned themselvesextensively with the antimicrobial properties of 1,2-diols, hithertothere has been no indication that mixtures of two, three or morestraight-chain 1,2-alkanediols, the chain lengths of which (i) aredifferent and (ii) in each case are in the range of 5 to 10 C atoms,possess an antimicrobial action (at least against selected germs) thatis distinctly improved in the individual case. The prior art also gaveno incentive to use such mixtures (combinations) as antimicrobial activecompounds.

For instance, although JP 11322591 A discloses that the dosage ofspecific conventional antiseptic microbicides can be reduced in that a1,2-alkanediol with, for example 5, 6 or 8 C atoms in the chain isadded, it cannot be seen from this publication that a mixture of two,three or more straight-chain 1,2-alkanediols, the chain lengths of which(i) are different and (ii) in each case are in the range of 5 to 10 Catoms, constitute an antimicrobial (combination) active compound whichhas an extremely high activity against at least selected germs.

Quite similarly, JP 11310506 discloses a synergistic effect in the caseof the combination of paraben with 1,2-pentanediol, 1,2-hexanediol or1,2-octanediol. However, the finding of the synergistic intensificationof the antimicrobial properties of the said 1,2-alkanediols, on whichthe present invention is based, likewise cannot be seen from JP 11310506A.

In U.S. Pat. No. 6,123,953 certain synergistic effects between a1,2-alkanediol having a chain length in the range of 5 to 14 carbonatoms and a glyceryl polymethacrylate gel are described. However, the USdocument does not disclose a combination of 1,2-alkanediols andcertainly does not disclose at all such combinations (mixtures) havingan antimicrobial action which is intensified compared with the action ofthe individual substances.

EP 0 524 548 A1 discloses specific antimicrobially active mixtures thatcontain, in addition to (A) an antimicrobially active aromatic alcoholof the Formula 1

in which R² is hydrogen or an alkyl group having 1 to 4 C atoms and n isan integer from 1 to 6, (B) an antimicrobially active 1,2- or 1,3-diolof the Formula R²—CHOH—(CHR³)_(X)—CH₂OH, where x=0 or 1 and, if x=0, R²is an alkyl group having 6 to 22 C atoms or an alkoxymethyl or2-hydroxyalkoxymethyl group having, in each case 6 to 22 C atoms in thealkoxy group and, if x=1, the group R² is hydrogen and R³ has one of theabovementioned meanings for R², the components being in a mass ratio of9:1 to 1:9. The antimicrobially active mixtures disclosed are said to besuitable for the preparation of antiseptically active skin cleansingagents and for the preservation of aqueous formulations of microbiallydegradable or perishable substances. However, it is not obvious fromthis technical teaching to mix two, three or more straight-chain1,2-alkanediols, the chain lengths of which (i) are different and (ii)in each case are in the range of 5 to 10 C atoms, and to use theresulting mixture as an antimicrobial active compound. In particular, EP0 524 548 A1 gives no indication of the possibility that such alkanediolmixtures could have a synergistically intensified antimicrobial(combination) action, so that, in particular (as possible within theframework of the present invention), the aromatic alcohols of theFormula 1 could be dispensed with.

JP 10053510 discloses combinations of pentanediol and phenoxyethanol asantiseptic agents for cosmetics.

DE 199 24 496 A1 discloses mixtures of at least one polyhydric alcoholhaving 5 to 15 carbon atoms (for example 1,2-pentanediol, hexanediol oroctanediol) and a trialkyl citrate for combating human body odour.

Combinations of 2,4,6-cycloheptatrien-1-one-2-hydroxy-4(1-methyl-ethyl)with specific polyols are described in EP 1 000 542 A1. 1,2-octanediol,1,2-pentanediol and/or octoxyglycerol can also be used as polyol inthese combinations. However, no indication of the use of a mixture of1,2-octanediol and 1,2-pentanediol or such a mixture of two, three ormore straight-chain 1,2-alkanediols as antimicrobial active compound canbe found in this publication. Rather, the function of the1,2-alkanediols disclosed in EP 1 000 542 A1 remains unclear; inparticular, from paragraph [0048] of EP 1 000 542 A1 the impression isgained that they would have only an inadequate antimicrobial activitywithout the presence of the said cycloheptatrienone derivative (oralternatively of a sodium capryl-lactyl-lactylate).

WO 99/56715 and WO 99/56716 relate to the use of 1,2-hexanediol asdeodorant or antiperspirant. These publications as well do not disclosea synergistic intensification of the antimicrobial activity bycombinations consisting of at least two diols of the general Formula 1.

In addition, a series of further documents relate to applications of1,2-diols, but without discussing a synergistic intensification of theantimicrobial activity thereof by combinations consisting of at leasttwo diols. To this extent, reference is made to the following documents:FR 2,755,371; WO 99/11237; WO 99/56715; JP 20 0044419; JP 11 335258; JP10 053510; J. Food Sc. 42(3), 699-701; DE 199 24 496 und JP 20 0148720.

In view of the comprehensive research on the antimicrobial activity ofindividual diols having a chain length in the range of 5 to 10 C atomsit was now particularly surprising that mixtures of two, three or morestraight-chain 1,2-alkanediols, the chain lengths of which (i) aredifference and (ii) in each case are in the range of 5 to 10 C atomsdisplay a strongly synergistic activity and are clearly superior to theindividually dosed 1,2-diols having chain lengths in the same range inthe same concentration, in particular with regard to the reduction ingerm time. In particular, a CFU value (CFU=number of colony-formingunits) of 0 can be achieved in the individual case only with the saidmixtures according to the invention.

The use of a mixture of (a) 1,2-hexanediol and 1,2-octanediol (b)1,2-hexanediol and 1,2-decanediol, (c) 1,2-pentanediol, 1,2-hexanedioland 1,2-octanediol, (d) 1,2-hexanediol, 1,2-octanediol and1,2-decanediol or (e) 1,2-pentanediol, 1,2-hexanediol and 1,2-decanediolis particularly preferred. In this context see also the examples furtherbelow.

Based on the total mass of the mixture of the diols, the proportion ofeach individual diol should be in the range of 1 to 99% (m/m), butpreferably in the range of 20 to 80% (m/m).

The 1,2-diol mixtures according to the invention are suitable not onlyfor the preservation of perishable products such as, for example,cosmetic products, pharmaceutical products or foods, but, because oftheir synergistically intensified antimicrobial activity, can also beused

(a) for the cosmetic treatment of microorganisms causing body odour,

(b) for the cosmetic treatment of microorganisms causing acne,

(c) for the cosmetic treatment of microorganisms causing mycoses and

(d) for the treatment of microorganisms on or in inanimate material.

The mixtures according to the invention develop their synergistic actionagainst a multiplicity of Gram-positive bacteria, Gram-negativebacteria, moulds and yeasts. There is a particularly good action againstGram-negative bacteria such as Escherichia coli and Pseudomonasaeruginosa, against yeasts such as Candida albicans and against fungisuch as Aspergillus niger. In this context the very good activity of the1,2-diol mixtures according to the invention against Aspergillus niger,a mould that can be controlled only with very great difficulty, is to beregarded as particularly advantageous, since the Applicant's own studieshave shown that when individual 1,2-diols with a chain length in therange of 5 to 10 C atoms are used the CFU value thereof cannot bereduced to the value 0.

The present invention also relates to corresponding methods for thecosmetic and/or therapeutic treatment of germs and specifically, inparticular, of (a) microorganisms causing body odour, (b) microorganismscausing acne and/or (c) microorganisms causing mycoses, comprising thetopical application of an antimicrobially effective amount of a mixtureof two, three or more straight-chain 1,2-alkanediols, the chain lengthsof which (i) are different and (ii) in each case are in the range of 5to 10 C atoms, the proportions of the said diols in the mixture beingset such that their antimicrobial action is synergistically intensified.

Preferred embodiments of the method according to the inventioncorrespond to the preferred embodiments of the use according to theinvention explained above.

The human skin is populated by a multiplicity of differentmicroorganisms which include the microorganisms already mentioned aboveas well as others. The majority of these microorganisms are notpathogenic and are irrelevant for the physiological condition of theskin and for its odour. Others, on the other hand, can have a decisiveinfluence on the healthy condition of the skin. Some microorganismswhich have a substantial influence on human skin flora are given inTable 1.

As the Applicant's own research now showed, the synergistically activemixtures according to the invention consisting of two, three or morestraight-chain 1,2-alkanediols, the chain lengths of which (i) aredifferent and (ii) in each case are in the range of 5 to 10 C atoms, notonly have a good action against the germs already mentioned above butalso against Staphylococcus epidermidis, Brevibacterium epidermidis,Propionibacterium acnes as well as against Trichophyton andEpidermophyton species, so that they can also be used as agents for thetreatment (control) of underarm odour and foot odour and of body odourin general, as agents for the control of acne, as anti-dandruff agentsand for the treatment of mycoses (in particular dermatomycoses (againsee Table 1).

TABLE 1 Microorganisms: Staphylococcus epidermidis underarm odour, bodyodour in general Staphylococcus aureus atopic eczemas; wound infectionCorynebacterium xerosis underarm odour Brevibacterium epidermidisunderarm odour; foot odour Propionibacterium acnes acne Escherichia coliwound infection Pseudomonas aeruginosa wound infection Malassezia furfurdevelopment of dandruff (syn. Pityrosporum ovale) Candida albicansgeneral candidoses Trichophyton mentagrophytes skin and nail mycosesTrichophyton rubrum skin and nail mycoses Epidermophyton floccosum skinand nail mycoses Aspergillus niger mould infestation

The following supplementary remarks may be made in this context:

As a result of the bacterial degradation of substances produced in thebody and contained in perspiration, such as, for example, unsaturatedfatty acids, decomposition products with an unpleasant odour that canhave a severe effect on bodily wellbeing are formed from precursors thathave a more or less weak odour. In cosmetics, products that eithersuppress the formation of body perspiration (so-called antiperspirants)or substances that inhibit the growth of the bacteria of the human skinthat are responsible for odour formation (deodorants) are used toprevent the formation of the substances responsible for body odour.Species of bacteria such as Staphylococcus epidermidis, Corynebacteriumxerosis and Brevibacterium epidermidis generally have decisiveresponsibility for the formation of underarm and foot odour or bodyodour. In the cosmetics industry there is therefore an ongoing need fornew agents for the treatment of microorganisms causing this and otherbody odour (including underarm and foot odour).

A microorganism that causes acne is Propionibacterium acnes, which is agerm that grows anaerobically. The cosmetics industry is continuallylooking for agents for the treatment of this germ and othermicroorganisms that cause acne.

All areas of the human skin can be infested by mycoses (in particulardermatomycoses and nail mycoses). Areas of the skin on which moistureand warmth can build up as a result of wearing clothing, shoes orjewellery are particularly frequently affected. Fungus diseases of thefingernail and toenail regions are experienced as being particularlyunpleasant. Various species of Trichophyton and Epidermophytonfrequently have decisive responsibility for the formation of mycoses.The cosmetics industry is continuously searching for novel agents forthe treatment of microorganisms causing these and other mycoses.

Within the context of the present text, “treatment” is understood to beany form of influence on the microorganisms concerned by means of whichthe reproduction of these microorganisms is inhibited and/or themicroorganisms are killed.

Preferably, the use concentration of the mixtures according to theinvention consisting of two, three or more straight-chain1,2-alkanediols, the chain lengths of which (i) are different and (ii)in each case are in the range of 5 to 10 C atoms, in the case of use aspreservative in a food or as antimicrobial active compound in a cosmeticor pharmaceutical end product is in the range between 0.01 and 30%(m/m), but particularly preferentially in the range between 0.1 and 5%(m/m), in each case based on the total mass of the food or end product.

Also in a preferred method according to the invention for the cosmeticand/or therapeutic treatment of (a) microorganisms causing body odour,(b) microorganisms causing acne and/or (c) microorganisms causingmycoses, the use concentration of the synergistically active mixturesaccording to the invention is in the range between 0.01 and 30% (m/m)and particularly preferentially in the range between 0.1 and 5% (m/m),in each case based on the total mass of the cosmetic or pharmaceuticalproduct which contains the mixture.

In this context the synergistically active diol mixtures can be used (a)prophylactically or (b) as needed.

The concentration of the amount of active compound that is, for example,to be applied daily is variable and depends on the physiologicalcondition of the test person as well as on parameters specific to theindividual, such as age or body weight. The synergistically active diolmixtures according to the invention can be used both on their own andalso in combination with further antimicrobially active substances.

It is furthermore pointed out that in the context of the present textthe terms 1,2-diol includes both the corresponding 2S-configuredenantiomer and also the 2R-configured enantiomer as well as arbitrarymixtures of these 2S- and 2R-configured enantiomers. It is true that forcommercial reasons it is particularly advantageous to use mixtures ofracemates of the relevant diols to control microorganisms, since theseare particularly easily accessible by a synthetic route; however, thepure enantiomers or non-racemic mixtures of these enantiomers are alsosuitable for the purposes according to the invention.

Finally, the present invention also relates to correspondingantimicrobial compositions comprising:

-   (a) a mixture of two, three or more straight-chain 1,2-alkanediols,    the chain lengths of which (i) are different and (ii) in each case    are in the range of 5 to 10 C atoms, and-   (b) an excipient compatible with the said mixture, as well as    antimicrobial compositions comprising:-   (a) a mixture of two, three or more straight-chain 1,2-alkanediols,    the chain lengths of which (i) are different and (ii) in each case    are in the range of 5 to 10 C atoms, as antimicrobial active    compound, and-   (b) an excipient compatible with the said mixture and also,    optionally,-   a further antimicrobial active compound that does not comprise a    straight-chain 1,2-alkanediol.

With regard to the preferred embodiments of the antimicrobialcompositions according to the invention, what has been stated aboveapplies correspondingly.

Further uses/methods and compositions according to the invention can betaken from the following explanations and the appended patent claims.

In particular insofar as they are used against germs causing body odour,compositions that contain a synergistically active mixture according tothe invention are as a rule applied topically in the form of solutions,creams, lotions, gels, sprays or the like. For other purposes, an oral(tablet, capsules, powders, drops), intravenous, intraoccular,intraperitineal or intramuscular application or an application in theform of an impregnated bandage is sensible in some cases.

The synergistically active mixtures of 1,2-alkanediols used according tothe invention can be incorporated without difficulty in conventionalcosmetic or dermatological/keratological formulations such as, interalia, pump sprays, aerosol sprays, creams, shampoos, ointments,tinctures, lotions, nail care products (for example nail varnishes, nailvarnish removers, nail balsams) and the like. In this context it is alsopossible, and in some cases advantageous, to combine the synergisticmixtures of 1,2-alkanediols used according to the invention with furtheractive compounds, for example with other substances having anantimicrobial, antimycotic and/or antiviral action. In this context thecosmetic and/or dermatological/keratological formulations containing thesynergistically active 1,2-alkanediols can otherwise be of customarycomposition and serve for treatment of the skin and/or the hair in thesense of a dermatological or keratological treatment or of a treatmentin the sense of care cosmetics. However, they can also be used inmake-up products in decorative cosmetics.

If the synergistic mixtures of 1,2-alkanediols according to theinvention are used as active compounds for the preservation of organicmaterial, a further preservative, or several further preservatives, canadvantageously additionally be used. Preferably, preservatives such asbenzoic acid, the esters and salts thereof, propionic acid and saltsthereof, salicylic acid and salts thereof, 2,4-hexanoic acid (sorbicacid) and salts thereof, formaldehyde and paraformaldehyde,2-hydroxybiphenyl ether and salts thereof,2-zincsulphidopyridine-N-oxide, inorganic sulphites and bisulphites,sodium iodate, chlorobutanolum,4-ethylmercury-(II)5-amino-1,3-bis(2-hydroxy)benzoic acid, salts andesters thereof, dehydratcetic (sic) acid, formic acid,1,6-bis(4-amidino-2-bromophenoxy)-n-hexane and salts thereof, the sodiumsalt of ethylmercury-(II)-thiosalicylic acid, phenylmercury and saltsthereof, 10-undecylenic acid and salts thereof,5-amino-1,3-bis(2-ethylhexyl)-5-methyl-hexahydropyrimidine,5-bromo-5-nitro-1,3-dioxane, 2-bromo-2-nitro-1,3-propanediol,2,4-dichlorobenzyl alcohol,N-(4-chlorophenyl)-N′-(3,4-dichlorophenyl)-urea, 4-chloro-m-cresol,2,4,4′-trichloro-2′-hydroxy-diphenyl ether, 4-chloro-3,5-dimethylphenol,1,1′-methylene-bis(3-(1-hydroxymethyl-2,4-dioximidazolidin-5-yl)urea),poly-(hexamethylene diguanide) hydrochloride, 2-phenoxyethanol,hexamethylentetramine,1-(3-chloroallyl)-3,5,7-triaza-1-azonia-adamantane chloride,1(4-chlorphenoxy)-1(1H-imidazol-1-yl)-3,3-dimethyl-2-butanone,1,3-bis-(hydroxy-methyl)-5,5-dimethyl-2,4-imidazolidinedione, benzylalcohol, Octopirox, 1,2-dibromo-2,4-dicyanobutane,2,2′-methylene-bis(6-bromo-4-chloro-phenol), bromo-chlorophene, mixtureof 5-chloro-2-methyl-3(2H)-isothiazolinone and 2-methyl-3(2H)isothiazolinone with magnesium chloride and magnesium nitrate,2-benzyl-4-chlorophenol, 2-chloracetamide, chlorhexidine, chlorhexidineacetate, chlorhexidine gluconate, chlorhexidine hydrochloride,1-phenoxy-propan-2-ol, N-alkyl (C₁₂-C₂₂) trimethyl-ammonium bromide andchloride, 4,4-dimethyl-1,3-oxazolidine,N-hydroxymethyl-N-(1,3-di(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl)-N′-hydroxy-methylurea, 1,6-bis(4-amidino-phenoxy)-n-hexane and salts thereof,glutaraldehyde 5-ethyl-1-aza-3,7-dioxabicyclo(3.3.0)octane,3-(4-chlorphenoxy)-1,2-propanediol, hyamine,alkyl-(C₈-C₁₈)-dimethyl-benzyl-ammonium chloride,alkyl-(C₈-C₁₈)-dimethyl-benzyl ammonium bromide,alkyl-(C₈-C₁₈)-dimethyl-benzylammonium saccharinate, benzylhemiformal,3-iodo-2-propinyl-butyl carbamate, or sodium hydroxymethyl-aminoacetateare preferably chosen here. The advantage of active compoundcombinations consisting of (a) a synergistic mixture of 1,2-alkanediolsaccording to the invention and (b) at least one further preservative,which surprisingly can be achieved, will be explained in more detail onthe basis of Example 3.

If the synergistic mixtures of 1,2-alkanediols according to theinvention are to be used mainly for the inhibition of the growth ofundesired microorganisms on or in animal organisms, a combination withfurther antibacterial or antimycotic active compounds can beadvantageous in some cases here as well. Further active compounds thatare worthy of mention in this regard are, in addition to the large groupof conventional antibiotics, in particular the products relevant forcosmetics, such as triclosan, climbazol, octoxyglycerol, Octopirox(1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridone,2-aminoethanol), chitosan, farnesol, glycerol monolaurate orcombinations of the said substances, which, inter alia, are used againstunderarm odour, foot odour or dandruff.

In addition, the synergistic mixtures of 1,2-alkanediols can also beused particularly advantageously in combination withperspiration-inhibiting active compounds (antiperspirants) forcontrolling body odour. Perspiration-inhibiting active compounds usedare, in particular, aluminium salts, such as aluminium chloride,aluminium chlorohydrate, nitrate, sulphate, acetate etc. In addition,however, the use of zinc, magnesium and zirconium compounds can also beadvantageous. Essentially the aluminium salts and—to a somewhat lesserextent—aluminium/zirconium salt combinations have proved their worth foruse in cosmetic and dermatological antiperspirants. The partiallyneutralised aluminium hydroxychlorides, which are thus better toleratedby the skin but are not quite as effective, are also worthy of mention.In addition to aluminium salts, further substances can also be used,such as, for example, a) protein-precipitating substances such as, interalia, formaldehyde, glutaraldehyde, natural and synthetic tanning agentsand also trichloroacetic acid, which give rise to surface closure of thesweat glands, b) local anaesthetics (inter alia dilute solutions of, forexample, lidocaine, prilocaine or mixtures of such substances) thatswitch off the sympathetic supply of the sweat glands by blocking theperipheral nerve paths, c) zeolites of the X, A or Y type, which inaddition to reducing sweat secretion also act as adsorbents for badodours, and d) botulinus toxin (toxin of the bacterium Chlostridiumbotulinum), which is also used in the case of hyperhidrosis, apathologically increased sweat secretion, and the action of which isbased on an irreversible blockage of the release of the transmittersubstance acetylcholine relevant for sweat secretion.

If the synergistic mixtures of 1,2-alkanediols according to theinvention are to be used for the antimicrobial treatment of a surface(for example of a human or animal body), a combination with (metal)chelating agents can be advantageous in some cases. In this context,(metal) chelating agents that are preferably to be used are, inter alia,α-hydroxy fatty acids, phytic acid, lactoferrin, α-hydroxy acids, suchas, inter alia, citric acid, lactic acid and malic acid, as well ashumic acids, bile acids, bile extracts, bilirubin, biliverdin or EDTA,EGTA and derivatives thereof.

For use, the cosmetic and/or dermatologically active synergisticmixtures of 1,2-alkanediols according to the invention are applied tothe skin and/or the hair in an adequate amount in the manner customaryfor cosmetics and dermatological products. In this context cosmetic anddermatological formulations that contain a mixture according to theinvention and additionally act as a sunscreen offer particularadvantages. Advantageously, these formulations contain at least one UVAfilter and/or at least one UVB filter and/or at least one inorganicpigment. In this context the formulations can be in various forms, suchas are, for example, customarily employed for sunscreen formulations.Thus, they can be, for example, a solution, an emulsion of thewater-in-oil (W/O) type or of the oil-in-water (O/W) type or a multipleemulsion, for example of the water-in-oil-in-water (W/O/W) type, a gel,a hydrodispersion, a solid stick or also an aerosol.

As mentioned, formulations that contain a synergistic mixture of1,2-alkanediols can advantageously be combined with substances thatabsorb UV radiation, the total amount of the filter substances being,for example, 0.01% (m/m) to 40% (m/m), preferably 0.1% to 10% (m/m), inparticular 1.0 to 5.0% (m/m), based on the total weight of theformulations, in order to make available cosmetic formulations thatprotect the hair and/or the skin against ultraviolet radiation.

If the formulations according to the invention contain UVB filtersubstances, these can be oil-soluble or water-soluble. Advantageousoil-soluble UVB filters are, for example: 3-benzylidenecamphorderivatives, preferably 3-(4-methylbenzylidene)camphor,3-benzylidenecamphor; 4-aminobenzoic acid derivatives, preferably2-ethylhexyl 4-(dimethylamino)-benzoate, amyl 4-(dimethylamino)benzoate,esters of cinnamic 1 preferably 2-ethylhexyl 4-methoxycinnamate,isopentyl 4-methoxycinnamate; esters of salicylic acid, preferably2-ethylhexyl salicylate, 4-isopropylbenzyl salicylate, homomethylsalicylate, derivatives of benzophenone, preferably2-hydroxy-4-methoxybenzophenone,2-hydroxy-4-methoxy-4′-methylbenzophenone,2,2′-dihydroxy-4-methoxybenzophenone, esters of benzalmalonic acid,preferably di(2-ethylhexyl) 4-methoxybenzalmalonate,2,4,6-trianilino-(p-carbo-2′-ethyl-1′-hexyloxy)-1,3,5-triazine.Advantageous water-soluble UVB filters are, for example, salts of2-phenylbenzimidazole-5-sulphonic acid, such as the sodium, potassium ortriethanolammonium salt thereof, and also the sulphonic acid itself;sulphonic acid derivatives of benzophenones, preferably2-hydroxy-4-methoxybenzophenone-5-sulphonic acid and salts thereof;sulphonic acid derivatives of 3-benzylidenecamphor, such as, forexample, 4-(2-oxo-3-bornylidenemethyl)benzenesulphonic acid,2-methyl-5-(2-oxo-3-bornylidene-methyl)sulphonic acid and salts thereofand also 1,4-di(2-oxo-10-sulpho-3-bornylidenemethyl)-benzene and saltsthereof (the corresponding 10-sulphato compounds, for example thecorresponding sodium, potassium or triethanolammonium salt) and alsobenzene-1,4-di(2-oxo-3-bornylidene)methyl-10-sulphonic acid.

The above list of the said UVB filters that can be used in combinationwith the synergistic mixtures of 1,2-alkanediols according to theinvention should, of course, not be understood as definitive. It canalso be advantageous to employ UVA filters, such as are customarilycontained in cosmetic formulations. These substances are preferablyderivatives of dibenzoylmethane, in particular1-(4′-tert.-butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione and1-phenyl-3-(4′-isopropylphenyl)propane-1,3-dione.

In cosmetic formulations, the synergistic mixtures of 1,2-alkanediolsaccording to the invention can advantageously be combined with cosmeticauxiliaries, such as are customarily used in such formulations, thus,for example, with: antioxidants; perfume oils; agents to preventfoaming; colourants; pigments that have a colouring action; thickeners;surface-active substances; emulsifiers; plasticizing substances;moistening and/or moisture-retaining substances; fats, oils, waxes;other conventional constituents of a cosmetic formulation, such asalcohols, polyols, polymers, foam stabilisers; electrolytes, organicsolvents or silicone derivatives.

A high content of treatment substances is usually advantageous informulations containing synergistically active mixtures of1,2-alkanediols for the topical prophylactic or cosmetic treatment ofthe skin. According to a preferred embodiment, the compositions containone or more animal and/or vegetable treatment fats and oils, such asolive oil, sunflower oil, purified soya oil, palm oil, sesame oil,rapeseed oil, almond oil, borage oil, evening primrose oil, coconut oil,shea butter, jojoba oil, sperm oil, beef tallow, neatsfood oil and lard,and also optionally further treatment constituents, such as, forexample, fatty alcohols having 8-30 C atoms. Here the fatty alcohols canbe saturated or unsaturated and straight-chain or branched. For example,decanol, decenol, octanol, octenol, dodecanol, dodecenol, octadienol,decadienol, dodecadienol, oleyl alcohol, ricinol alcohol, erucicalcohol, stearyl alcohol, isostearyl alcohol, cetyl alcohol, laurylalcohol, myristyl alcohol, arachidyl alcohol, capryl alcohol, capricalcohol, linoleyl alcohol, linolenyl alcohol and behenyl alcohol, aswell the guerbet alcohols thereof can be used, in which context it wouldbe possible to extend the list virtually arbitrarily by furtherstructurally chemically related alcohols. The fatty alcohols preferablyoriginate from natural fatty acids, and usually are prepared from thecorresponding esters of the fatty acids by reduction. Furthermore, fattyalcohol fractions that are formed from naturally occurring fats and fatoils by reduction, such as, for example, beef tallow, peanut oil, colzaoil, cottonseed oil, soya oil, sunflower oil, palm kernel oil, linseedoil, maize oil, castor oil, rapeseed oil, sesame oil, cocoa butter andcocoa fat, can be used.

In addition, the treatment substances that can preferably be combinedwith the synergistic mixtures of 1,2-alkanediols according to theinvention also include

-   -   ceramides, ceramides being understood to be N-acylsphingosines        (fatty acid amides of sphingosine) or synthetic analogues of        such lipids (so-called pseudo-ceramides), which clearly improve        the water retention capacity of the stratum corneum.    -   phospholipids, for example soya lecithin, egg lecithin and        cephalins    -   vaseline, paraffin and silicone oils; the latter include, inter        alia, dialkyl- and alkylaryl-siloxanes, such as        dimethylpolysiloxane and methylphenylpolysiloxane, as well as        the alkoxylated and quaternised derivatives thereof.

Animal and/or vegetable hydrolysed proteins can advantageously also beadded to the synergistic mixtures of 1,2-alkanediols according to theinvention. In this regard, in particular elastin, collagen, keratin,lactoprotein, soya protein, oat protein, pea protein, almond protein andwheat protein fractions or corresponding hydrolysed proteins, but alsothe condensation products thereof with fatty acids, and also quaternisedhydrolysed proteins are advantageous, the use of vegetable hydrolysedproteins being preferred.

Insofar as a cosmetic or dermatological formulation containing asynergistic mixture of 1,2-alkanediols according to the invention is asolution or lotion, the solvents used can be:

-   -   water or aqueous solutions;    -   fatty oils, fats, waxes and other natural and synthetic fatty        bodies, preferably esters of fatty acids with alcohols having a        low C number, for example with isopropanol, propylene glycol or        glycerol, or esters of fatty alcohols with alkanoic acids having        a low C number or with fatty acids;    -   alcohols, diols or polyols having a low C number, as well as the        ethers thereof, preferably ethanol, isopropanol, propylene        glycol, glycerol, ethylene glycol, ethylene glycol monoethyl or        monobutyl ether, propylene glycol monomethyl, monoethyl or        monobutyl ether, diethylene glycol monomethyl or monoethyl ether        and analogous products. In particular, mixtures of the        abovementioned solvents are used. In the case of alcoholic        solvents, water can be a further constituent.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also containantioxidants, it being possible to use all antioxidants suitable orcustomary for cosmetic and/or dermatological applications.Advantageously, the antioxidants are selected from the group consistingof amino acids (for example glycine, histidine, tyrosine, tryptophan)and the derivatives thereof, imidazoles (for example urocanic acid) andthe derivatives thereof, peptides such as D,L-carnosine, D-carnosine,L-carnosine and the derivatives thereof (for example anserine),carotinoids, carotenes (for example α-carotene, β-carotene, lycopene)and the derivatives thereof, lipoic acid and the derivatives therefore(for example dihydrolipoic acid), aurothioglucose, propylthiouracil andother thiols (for example thioredoxin, glutathione, cysteine, cystine,cystamine and the glycosyl, N-acetyl, methyl, ethyl, propyl, amyl,butyl, lauryl, palmitoyl, oleyl, γ-linoleyl, cholesteryl and glycerylesters thereof) as well as the salts thereof, dilauryl thiodipropionate,distearyl thiodipropionate, thiodipropionic acid and the derivativesthereof (esters, ethers, peptides, lipids, nucleotides, nucleosides andsalts) and also sulphoximine compounds (for example buthioninesulphoximines, homocysteine sulphoximine, buthionine sulphones, penta-,hexa-, hepta-thionine sulphoximine) in very low tolerated doses, andalso (metal) chelating agents, for example α-hydroxy fatty acids,palmitic acid, phytic acid, lactoferrin, α-hydroxy acids (for examplecitric acid, lactic acid, malic acid), humic acid, bile acid, bileextracts, bilirubin, biliverdin, EDTA, EGTA and the derivatives thereof,unsaturated fatty acids and the derivatives thereof (for exampleγ-linolenic acid, linoleic acid, oleic acid), folic acid and thederivatives thereof, ubiquinone and ubiquinol and the derivativesthereof, Vitamin C and derivatives (for example ascorbyl palmitate, Mgascorbyl phosphate, ascorbyl acetate), tocopherols and the derivativesthereof (for example Vitamin E acetate, Vitamin A and the derivativesthereof (Vitamin A palmitate) and also coniferyl benzoate of benzoinresin, rutinic acid and the derivatives thereof, ferrulic acid and thederivatives thereof, butylhydroxytoluene, butylhydroxyanisole,nordihydroguaiacic acid, nordihydroguaiaretic acid,trihydroxybutyrophenone, uric acid and the derivatives thereof, mannoseand the derivatives thereof, zinc and the derivatives thereof (forexample ZnO, ZnSO₄, selenium and the derivatives thereof (for exampleselenium methionine), stilbenes and the derivatives thereof (for examplestilbene oxide, trans-stilbene oxide) and also derivatives (salts,esters, ethers, sugars, nucleotides, nucleosides, peptides and lipids)of the said active compounds.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also contain vitamins andvitamin precursors, it being possible to use all vitamins and vitaminprecursors suitable or customary for cosmetic and/or dermatologicalapplications. Mention may be made here in particular of vitamins andvitamin precursors such as tocopherols, Vitamin A, nicotinic acid andnicotinomide, further vitamins of the B complex, in particular biotin,and Vitamin C, pantothenyl alcohol and the derivatives thereof, inparticular esters and ethers of pantothenyl alcohol, and alsoderivatives of pantothenyl alcohols obtained cationically, such as, forexample, pantothenyl alcohol triacetate, pantothenyl alcohol, monoethylether and the mono acetate thereof and also cationic pantothenyl alcoholderivatives.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also containanti-inflammatory active compounds and/or active compounds thatalleviate reddening and/or itching. In this context allanti-inflammatory active compounds and active compounds that alleviatereddening and/or itching that are suitable or customary for cosmeticand/or dermatological applications can be used. Advantageously, theanti-inflammatory active compounds and active compounds alleviatingreddening and/or itching that are used are steroidal anti-inflammatorysubstances of the corticosteroid type, such as, for example,hydrocortisone, dexamethasone, dexamethasone phosphate,methylprednisolone or cortisone, it being possible to expand the list byadding further steroidal anti-inflammatory agents. Non-steroidalanti-inflammatory agents can also be used. Oxicams, such as piroxicam ortenoxicam; salicylates, such as aspirin, Disalcid, Solprin or fendosal;acetic acid derivatives, such as diclofenac, fenclofenac, indomethacin,sulindac, tolmetin, or clindanac; fenamates, such as mefenamic,meclofenamic, flufenamic or niflumic; propionic acid derivatives, suchas ibuprofen, naproxen, benoxaprofen or pyrazoles, such asphenylbutazone, oxyphenylbutazone, febrazone or azapropazone, may bementioned here by way of example. Alternatively, naturalanti-inflammatory substances and substances that alleviate reddeningand/or itching can be used. Plant extracts, special highly active plantextract fractions and also highly pure active substances isolated fromplant extracts can be used. Extracts, fractions and active substancesfrom camomile, aloe vera, Commiphora species, Rubia species, willows,willow-herb, oats and pure substances such as, inter alia, bisabolol,apigenin-7-glucoside, boswellic acid, phytosterols, glycyrrhizine,glabridin or licochalkon A are particularly preferred. The formulationscontaining synergistic mixtures of 1,2-alkanediols can also containmixtures of two or more anti-inflammatory active compounds.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also contain furtheractive compounds having a skin lightening action. In this context allskin lightening active compounds that are suitable or customary forcosmetic and/or dermatological applications can be used according to theinvention. Advantageous skin lightening active compounds are, to thisextent, kojic acid, hydroquinone, arbutin, ascorbic acid, magnesiumascorbylphosphate, liquorice root extracts and the constituents thereofglabridin or licochalkon A, extracts from Rumex and Ramulus species,extracts from pine species (Pinus) and extracts from Vitis species,which, inter alia, contain skin-lightening stilbene derivatives.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also contain activecompounds having a skin-tanning action. To this extent all skin-tanningactive compounds that are suitable or customary for cosmetic and/ordermatological applications can be used. Dihydroxyacetone (DHA;1,3-dihydroxy-2-propanone) may be mentioned here by way of example. DHAcan be either in monomer or in dimer form, the proportion of dimerspredominating in crystalline form.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also contain mono- di-and oligo-saccharides, such as, for example, glucose, galactose,fructose, mannose, and lactose.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also contain plantextracts, which are usually prepared by extraction of the completeplant, but in individual cases are also prepared exclusively fromblossom and/or leaves, wood, bark or roots of the plant. With regard tothe plant extracts that can be used, reference is made in particular tothe extracts that are listed in the table starting on page 44 of thethird edition of the Leitfaden zur Inhaltsstoffdeklaration kosmetischerMittel, (Guide to the Declaration of Constituents of Cosmetic Agents),published by the Industrieverband Körperpflegemittel und Waschmittele.V. (IKW), Frankfurt. The extracts from aloe, Hamamelis, algae, oakbark, willow-herb, stinging nettles, dead nettles, hops, camomile,milfoil, arnica, calendula, burdock root, horse-tail, hawthorn, lindenblossom, almonds, pine needles, horsechestnut, sandalwood, juniper,coconut, mango, apricot, orange, lemon, lime, grapefruit, apple, greentea, grapefruit seed, wheat, oats, barley, sage, thyme, basil, rosemary,birch, mallow, bitter-crass, willow bark, restharrow, coltsfoot,althaea, ginseng and ginger root are particularly advantageous. Amongstthese, the extracts from aloe vera, camomile, algae, rosemary.calendula, ginseng, cucumber, sage, stinging nettles, linden blossom,arnica and Hamamelis are particularly preferred. Mixtures of two or moreplant extracts can also be employed. Extraction agents that can be usedfor the preparation of the said plant extracts can be, inter alia,water, alcohols and mixtures thereof. Amongst the alcohols, loweralcohols, such as ethanol and isopropanol, but also polyhydric alcohols,such as ethylene glycol, propylene glycol and butylene glycol arepreferred in this context, and specifically both as sole extractingagent and also in mixtures with water. The plant extracts can be used inthe pure form or also in dilute form.

Cosmetic formulations that contain synergistic mixtures of1,2-alkanediols according to the invention can also contain anionic,cationic, non-ionic and/or amphoteric surfactants, especially ifcrystalline or microcrystalline solids, for example inorganicmicropigments, are to be incorporated into the formulations. Surfactantsare amphiphilic substances that are able to dissolve organic, non-polarsubstances in water. In this context the hydrophilic parts of asurfactant molecule are usually polar functional groups, for example,—COO⁻, —OSO₃ ²⁻, —SO₃ ⁻, whilst the hydrophobic parts are as a rulenon-polar hydrocarbon radicals. Surfactants are generally classifiedaccording to the nature and charge of the hydrophilic part of themolecule. Four groups can be differentiated here:

anionic surfactants,

cationic surfactants,

amphoteric surfactants and

non-ionic surfactants.

Anionic surfactants usually contain carboxylate, sulphate or sulphonategroups as functional groups. In aqueous solution they form negativelycharged organic ions in the acid or neutral medium. Cationic surfactantsare characterised virtually exclusively by the presence of a quaternaryammonium group. In aqueous solution they form positively charged organicions in the acid or neutral medium. Amphoteric surfactants contain bothanionic and cationic groups and accordingly behave like anionic orcationic surfactants in aqueous solutions, depending on the pH value.They have a positive charge in a strongly acid medium and a negativecharge in an alkaline medium. In the neutral pH range, on the otherhand, they are zwitter ionic. Polyether chains are typical of non-ionicsurfactants. Non-ionic surfactants do not form ions in an aqueousmedium.

A. Anionic Surfactants

Anionic surfactants that can advantageously be used are acylamino acids(and the salts thereof), such as

-   -   acylglutamates, for example, sodium acylgultamate,        di-TEA-palmitoyl aspartate and sodium capryl/caprin glutamate,    -   acylpeptides, for example, palmitoyl-hydrolysed lactoprotein,        sodium cocoyl-hydrolysed soya protein and sodium/potassium        cocoyl-hydrolysed collagen,    -   sarcosinates, for example, myristoyl sarcosine, TEA lauroyl        sarcosinate, sodium lauroyl sarcosinate and sodium cocoyl        sarcosinate,    -   taurates, for example, sodium lauroyl taurate and sodium        methylcocoyl taurate,    -   acyl lactylates, lauroyl lactylate, caproyl lactylate    -   alaninates        carboxylic acids and derivatives, such as,    -   for example, lauric acid, aluminium stearate, magnesium        alkanolate and zinc undecylenate,    -   ester-carboxylic acids, for example calcium stearoyl lactylate,        laureth-6 citrate and sodium PEG-4 lauramidocarboxylate,    -   ether-carboxylic acids, for example sodium laureth-13        carboxylate and sodium PEG-6 cocamide carboxylate,        phosphoric acid esters and salts, such as, for example,        DEA-oleth-10 phosphate and dilaureth-4 phosphate,        sulphonic acids and salts, such as    -   acyl isothionates, for example sodium/ammonium        cocoyl-isethionate,    -   alkylarylsulphonates,    -   alkylsulphonates, for example sodium coconut monoglyceride        sulphate, sodium C₁₂₋₁₄ olefin-sulphonate sodium lauryl        sulphoacetate and magnesium PEG-3 cocamidosulphate,    -   sulphosuccinates, for example, dioctylsodium sulphosuccinate,        disodium laureth-sulphosuccinate, disodium laurylsulphosuccinate        and disodium undecylenamido MEA-sulphosuccinate        and        sulphuric acid esters, such as    -   alkyl ether sulphate, for example, sodium, ammonium, magnesium,        MIPA, TIPA laureth sulphate, sodium myreth sulphate and sodium        C12-13 pareth sulphate,    -   alkyl sulphates, for example, sodium, ammonium and TEA lauryl        sulphate.

B. Cationic Surfactants

Cationic surfactants that can advantageously be used are

-   -   alkylamines,    -   alkylimidazoles,    -   ethoxylated amines and    -   quaternary surfactants    -   RNH₂CH₂CH₂COO⁻ (at pH=7)    -   RNHCH₂CH₂COO—B⁺ (at pH=12) B⁺=arbitrary cation, for example Na⁺    -   esterquats

Quaternary surfactants contain at least one N atom that is covalentlybonded to 4 alkyl or aryl groups. This leads to a positive charge,irrespective of the pH value. Alkylbetaine, alkylamidopropylbetaine andalkylamidopropyl-hydroxysulfaine are advantageous. The cationicsurfactants used can furthermore preferably be chosen from the groupcomprising the quaternary ammonium compounds, in particularbenzyltrialkyl-ammonium chloride or bromide, such as, for example,benzyldimethylstearyl-ammonium chloride, and also alkyltrialkylammoniumsalts, for example cetyltrimethylammonium chloride or bromide,alkyldimethylhydroxy-ethylammonium chlorides or bromides,dialkyldimethylammonium chlorides or bromides,alkylamidoethyltrimethyl-ammonium ether sulphates, alkylpyridiniumsalts, for example lauryl- or cetyl-pyrimidinium chloride, imidazolinederivatives and compounds of a cationic nature, such as amine oxides,for example alkyldimethylamine oxides or alkylaminoethyldimethylamineoxides. Cetyltrimethyl-ammonium salts can be used particularlyadvantageously.

C. Amphoteric Surfactants

Amphoteric surfactants that can advantageously be used are

-   -   acyl-/dialkylethylenediamine, for example sodium        acylamphoacetate, disodium acylamphodipropionate, disodium        alkylamphodiacetate, sodium acylamphohydroxypropylsulphonate,        disodium acylampho-diacetate and sodium acylamphopropionate,    -   N-alkylamino acids, for example aminopropylalkylglutamide,        alkylaminopropionic acid, sodium alkylimidodipropionate and        lauroamphocarboxyglycinate.

D. Non-Ionic Surfactants

Non-ionic surfactants that can advantageously be used are

-   -   alcohols,    -   alkanolamides, such as cocamides MEA/DEA/MIPA,    -   amine oxides, such as cocoamidopropylamine oxide,    -   esters, that are formed by esterification of carboxylic acids        with ethylene oxide, glycerol, sorbitan or other alcohols,    -   ethers, for example ethoxylated/propoxylated alcohols,        ethoxylated/propoxylated esters, ethoxylated/propoxylated        glycerol esters, ethoxylated/propoxylated cholesterols,        ethoxylated/propoxylated triglyceride esters, ethoxylated        [lacuna] propoxylated lanolin, ethoxylated/propoxylated        polysiloxanes, propoxylated POE ethers and alkylpolyglycosides,        such as lauryl glucoside, decyl glycoside and coco glycoside.    -   sucrose esters and ethers    -   polyglycerol esters, diglycerol esters, monoglycerol esters    -   methylglucose esters, esters of hydroxy acids

The use of a combination of anionic and/or amphoteric surfactants withone or more non-ionic surfactants is also advantageous. Thesurface-active substance can be present in a concentration of between 1and 98% (m/m) in the formulations according to the invention containingsynergistic mixtures of 1,2-alkanediols, based on the total weight ofthe formulations.

Cosmetic or dermatological formulations that contain synergisticmixtures of 1,2-alkanediols according to the invention according to theinvention can also be in the form of emulsions.

The oil phase can advantageously be chosen from the following group ofsubstances:

-   -   mineral oils, mineral waxes    -   fatty oils, fats, waxes and other natural and synthetic fatty        bodies, preferably esters of fatty acids with alcohols having a        low C number, for example with isopropanol, propylene glycol or        glycerol, or esters of fatty alcohols with alkanoic acids having        a low C number or with fatty acids;    -   alkyl benzoates;    -   silicone oils, such as dimethylpolysiloxanes,        diethylpolysiloxanes, diphenylpolysiloxanes and mixed forms        therefrom.

Advantageously, (a) esters of saturated and/or unsaturated, branchedand/or straight-chain alkanecarboxylic acids having a chain length of 3to 30 C atoms and saturated and/or unsaturated, branched and/orstraight-chain alcohols having a chain length of 3 to 30 C atoms, (b)esters of aromatic carboxylic acids and saturated and/or unsaturated,branched and/or straight-chain alcohols having a chain length of 3 to 30C atoms can be used. Preferred ester oils are isopropyl myristate,isopropyl palmitate, isopropyl stearate, isopropyl oleate, n-butylstearate, n-hexyl laurate, n-decyl oleate, isooctyl stearate, isononylstearate, isononyl isononanoate, 2-ethylhexyl palmitate, 2-ethylhexyllaurate, 2-hexyldecyl stearate, 2-octyldodecyl palmitate, oleyl oleate,oleyl erucate, erucyl oleate, erucyl erucate and synthetic,semi-synthetic and natural mixtures of such esters, for example, jojobaoil.

Furthermore, the oil phase can advantageously be chosen from the groupcomprising the branched and straight-chain hydrocarbons and waxes, thesilicone oils, the dialkyl ethers, the group comprising the saturated orunsaturated, branched or straight-chain alcohols, and also the fattyacid triglycerides, specifically, the triglycerol esters of saturatedand/or unsaturated, branched and/or straight-chain alkanecarboxylicacids having a chain length of 8 to 24, in particular 12 to 18 C atoms.The fatty acid triglycerides can advantageously be chosen from the groupcomprising the synthetic, semi-synthetic and natural oils, for example,olive oil, sunflower oil, soya oil, peanut oil, rapeseed oil, almondoil, palm oil, coconut oil, palm kernel oil and more of the like.Arbitrary admixtures of such oil and wax components can alsoadvantageously be used. In some cases it is also advantageous to usewaxes, for example cetyl palmitate, as the sole lipid component of theoil phase; advantageously, the oil phase is chosen from the group thatconsists of 2-ethylhexyl isostearate, octyldodecanol, isotridecylisononanoate, isoeicosane, 2-ethylhexyl cocoate, C₁₂₋₁₅-alkyl benzoate,capryl-capric acid triglyceride and dicaprylyl ether. Mixtures ofC₁₂₋₁₅-alkyl benzoate and 2-ethylhexyl isostearate, mixtures ofC₁₂₋₁₅-alkyl benzoate and isotridecyl isononanoate and mixtures ofC₁₂₋₁₅-alkyl benzoate, 2-ethylhexyl isostearate and isotridecylisononanoate are particularly advantageous. The hydrocarbons paraffinoil, squalane and squalene can also advantageously be used.Advantageously, the oil phase can furthermore contain cyclic or linearsilicone oils or consist entirely of such oils, it being, however,preferred to use an additional content of other oil phase components inaddition to the silicone oil or the silicone oils. Cyclomethicone (forexample, decamethylcyclopentasiloxane) can advantageously be used assilicone oil. However, other silicone oils can also advantageously beused, for example undecamethylcyclotrisiloxane, polydimethylsiloxane andpoly(methyl-phenylsiloxane). Furthermore, mixtures of cyclomethicone andisotridecyl isononanoate and of cyclomethicone and 2-ethylhexylisostearate are particularly advantageous.

The aqueous phase of formulations that according to the inventioncontain synergistic mixtures of 1,2-alkanediols and are in the form ofan emulsion can comprise: alcohols, diols or polyols having a low Cnumber and also the ethers thereof, preferably ethanol, isopropanol,propylene glycol, glycerol, ethylene glycol, ethylene glycol monoethylor monobutyl ether, propylene glycol monomethyl, monoethyl or monobutylether, diethylene glycol monomethyl or monoethyl ether and analogousproducts, and also alcohols having a low C number, for example, ethanol,isopropanol, 1,2-propanediol, glycerol and also, in particular, one ormore thickeners, which thickener or thickeners can advantageously bechosen from the group comprising silicon dioxide, aluminium silicates,polysaccharides and the derivatives thereof, for example hyaluronicacid, xanthan gum, hydroxypropyl-methylcellulose, and particularlyadvantageously from the group comprising the polyacrylates, preferably apolyacrylate from the group comprising the so-called carbopols, forexample carbopols of types 980, 981, 1382, 2984, 5984, in each case ontheir own or in combination.

Formulations that contain synergistic mixtures of 1,2-alkanediolsaccording to the invention and are in the form of an emulsionadvantageously contain one or more emulsifiers. O/W emulsifiers can, forexample, advantageously be chosen from the group comprising thepolyethoxylated or polypropoxylated or polyethoxylated andpolypropoxylated products, for example:

the fatty alcohol ethoxylates

the ethoxylated wool wax alcohols,

the polyethylene glycol ethers of the general formulaR—O—(—CH₂—CH₂—O—)_(n)—R′,

the fatty acid ethoxylates of the general formulaR—COO—(—CH₂—CH₂—O—)_(n)—H,

the etherified fatty acid ethoxylates of the general formulaR—COO—(—CH₂—CH₂—O—)_(n)—R′,

the esterified fatty acid ethoxylates of the general formulaR—COO—(—CH₂—CH₂—O—)_(n)—C(O)—R′,

the polyethylene glycol glycerol fatty acid esters

the ethoxylated sorbitan esters

the cholesterol ethoxylates

the ethoxylated triglycerides

the alkyl ether carboxylic acids of the general formulaR—COO—(—CH₂—CH₂—O—)_(n)—OOH,and n represents a number from 5 to 30,

the polyoxyethylene sorbitol fatty acid esters,

the alkyl ether sulphates of the general formulaR—O—(—CH₂—CH₂—O—)_(n)—SO₃—H

the fatty alcohol propoxylates of the general formulaR—O—(—CH₂—CH(CH₃)—O—)_(n)—H

the polypropylene glycol ethers of the general formulaR—O—(—CH₂—CH(CH₃)—O—)_(n)—R′

the propoxylated wool wax alcohols,

the esterified fatty acid propoxylatesR—COO—(—CH₂—CH(CH₃)—O—)_(n)—R′

the esterified fatty acid propoxylates of the general formulaR—COO—(—CH₂—CH(CH₃)—O—)_(n)—C(O)—R′

the fatty acid propoxylates of the general formulaR—COO—(—CH₂—CH(CH₃)—O—)_(n)—H,

the polypropylene glycol glycerol fatty acid esters

the propoxylated sorbitan esters

the cholesterol propoxylates

the propoxylated triglycerides

the alkyl ether carboxylic acids of the general formulaR—O—(—CH₂—CH(CH₃)—O—)_(n)—CH₂—COOH,

the alkyl ether sulphates and the acids on which these sulphates arebased of the general formulaR—O—(—CH₂—CH(CH₃)—O—)_(n)—SO₃—H,

the fatty alcohol ethoxylates/propoxylates of the general formulaR—O—X_(n)—Y_(m)—H

the polypropylene glycol ethers of the general formulaR—O—X_(n)—Y_(m)—R′

the esterified fatty acid propoxylates of the general formulaR—COO—X_(n)—Y_(m)—R′

the fatty acid ethoxylates/propoxylates of the general formulaR—COO—X_(n)—Y_(m)—H.

According to the invention, the polyethoxylated or polypropoxylated orpolyethoxylated and polypropoxylated O/W emulsifiers used areparticularly advantageously chosen from the group comprising substanceshaving HLB values of 11-18, very particularly advantageously having HLBvalues of 14.5-15.5, insofar as the O/W emulsifiers contain saturatedradicals R and R′. If the O/W emulsifiers contain unsaturated radicals Rand/or R′, or if there are isoalkyl derivatives, the preferred HLB valueof such emulsifiers can also be lower or higher.

It is advantageous to choose the fatty alcohol ethoxylates from thegroup comprising the ethoxylated stearyl alcohols, cetyl alcohols,cetylstearyl alcohols (cetearyl alcohols). The following areparticularly preferred:

polyethylene glycol(13) stearyl ether (Steareth-13),

polyethylene glycol(14) stearyl ether (Steareth-14),

polyethylene glycol(15) stearyl ether (Steareth-15),

polyethylene glycol(16) stearyl ether (Steareth-16),

polyethylene glycol(17) stearyl ether (Steareth-17),

polyethylene glycol(18) stearyl ether (Steareth-18),

polyethylene glycol(19) stearyl ether (Steareth-19),

polyethylene glycol(20) stearyl ether (Steareth-20),

polyethylene glycol(12) isostearyl ether (Isosteareth-12),

polyethylene glycol(13) isostearyl ether (Isosteareth-13),

polyethylene glycol(14) isostearyl ether (Isosteareth-14),

polyethylene glycol(15) isostearyl ether (Isosteareth-15),

polyethylene glycol(16) isostearyl ether (Isosteareth-16),

polyethylene glycol(17) isostearyl ether (Isosteareth-17),

polyethylene glycol(18) isostearyl ether (Isosteareth-18),

polyethylene glycol(19) isostearyl ether (Isosteareth-19),

polyethylene glycol(20) isostearyl ether (Isosteareth-20),

polyethylene glycol(13) cetyl ether (Ceteth-13),

polyethylene glycol(14) cetyl ether (Ceteth-14),

polyethylene glycol(15) cetyl ether (Ceteth-15),

polyethylene glycol(16) cetyl ether (Ceteth-16),

polyethylene glycol(17) cetyl ether (Ceteth-17),

polyethylene glycol(18) cetyl ether (Ceteth-18),

polyethylene glycol(19) cetyl ether (Ceteth-19),

polyethylene glycol(20) cetyl ether (Ceteth-20),

polyethylene glycol(13) isocetyl ether (Isoceteth-13),

polyethylene glycol(14) isocetyl ether (Isoceteth-14),

polyethylene glycol(15) isocetyl ether (Isoceteth-15),

polyethylene glycol(16) isocetyl ether (Isoceteth-16),

polyethylene glycol(17) isocetyl ether (Isoceteth-17),

polyethylene glycol(18) isocetyl ether (Isoceteth-18),

polyethylene glycol(19) isocetyl ether (Isoceteth-19),

polyethylene glycol(20) isocetyl ether (Isoceteth-20),

polyethylene glycol(12) oleyl ether (Oleth-12),

polyethylene glycol(13) oleyl ether (Oleth-13),

polyethylene glycol(14) oleyl ether (Oleth-14),

polyethylene glycol(15) oleyl ether (Oleth-15),

polyethylene glycol(12) lauryl ether (Laureth-12),

polyethylene glycol(12) isolauryl ether (Isolaureth12),

polyethylene glycol(13) cetyl stearyl ether (Ceteareth-13),

polyethylene glycol(14) cetyl stearyl ether (Ceteareth-14),

polyethylene glycol(15) cetyl stearyl ether (Ceteareth-15),

polyethylene glycol(16) cetyl stearyl ether (Ceteareth-16),

polyethylene glycol(17) cetyl stearyl ether (Ceteareth-17),

polyethylene glycol(18) cetyl stearyl ether (Ceteareth-18),

polyethylene glycol(19) cetyl stearyl ether (Ceteareth-19),

polyethylene glycol(20) cetyl stearyl ether (Ceteareth-20).

It is furthermore advantageous to choose the fatty acid ethoxylates fromthe following group:

polyethylene glycol(20) stearate, polyethylene glycol(21) stearate,

polyethylene glycol(22) stearate, polyethylene glycol(23) stearate,

polyethylene glycol(24) stearate, polyethylene glycol(25) stearate,

polyethylene glycol(12) isostearate, polyethylene glycol(13)isostearate,

polyethylene glycol(14) isostearate, polyethylene glycol(15)isostearate,

polyethylene glycol(16) isostearate, polyethylene glycol(17)isostearate,

polyethylene glycol(18) isostearate, polyethylene glycol(19)isostearate,

polyethylene glycol(20) isostearate, polyethylene glycol(21)isostearate,

polyethylene glycol(22) isostearate, polyethylene glycol(23)isostearate,

polyethylene glycol(24) isostearate, polyethylene glycol(25)isostearate,

polyethylene glycol(12) oleate, polyethylene glycol(13) oleate,

polyethylene glycol(14) oleate, polyethylene glycol(15) oleate,

polyethylene glycol(16) oleate, polyethylene glycol(17) oleate,

polyethylene glycol(18) oleate, polyethylene glycol(19) oleate,

polyethylene glycol(20) oleate.

Advantageously, sodium laureth-11-carboxylate can be used as ethoxylatedalkyl ether carboxylic acid or the salt thereof. Sodium laureth 1-4sulphate can advantageously be used as alkyl ether sulphate.Polyethylene glycol(30) cholesteryl ether can advantageously be used asethoxylated cholesterol derivative. Polyethylene glycol(25) soyasterolhas also proved useful. The polyethylene glycol(60) evening primroseglycerides can advantageously be used as ethoxylated triglycerides.

It is furthermore advantageous to choose the polyethylene glycolglycerol fatty acid esters from the group comprising polyethyleneglycol(20) glyceryl laurate, polyethylene glycol(21) glyceryl laurate,polyethylene glycol(22) glyceryl laurate, polyethylene glycol(23)glyceryl laurate, polyethylene glycol(6) glyceryl caprate/caprinate,polyethylene glycol(20) glyceryl oleate, polyethylene glycol(20)glyceryl isostearate, polyethylene glycol(18) glyceryl oleate/cocoate.

It is also advantageous to choose the sorbitan esters from the groupcomprising

polyethylene glycol(20) sorbitan monolaurate,

polyethylene glycol(20) sorbitan monostearate,

polyethylene glycol(20) sorbitan monoisostearate,

polyethylene glycol(20) sorbitan monopalmitate,

polyethylene glycol(20) sorbitan monooleate.

The following can be used as advantageous W/O emulsifiers: fattyalcohols having 8 to 30 carbon atoms, monoglycerol esters of saturatedand/or unsaturated, branched and/or straight-chain alkanecarboxylicacids having a chain length of 8 to 24, in particular 12 to 18 C atoms,diglycerol esters of saturated and/or unsaturated, branched and/orstraight-chain alkanecarboxylic acids having a chain length of 8 to 24,in particular 12 to 18 C atoms, monoglycerol ethers of saturated and/orunsaturated, branched and/or straight-chain alcohols having a chainlength of 8 to 24, in particular 12 to 18 C atoms, diglycerol ethers ofsaturated and/or unsaturated, branched and/or straight-chain alcoholshaving a chain length of 8 to 24, in particular 12 to 18 C atoms,propylene glycol esters of saturated and/or unsaturated, branched and/orstraight-chain alkanecarboxylic acids having a chain length of 8 to 24,in particular 12 to 18 C atoms and sorbitan esters of saturated and/orunsaturated, branched and/or straight-chain alkanecarboxylic acidshaving a chain length of 8 to 24, in particular 12 to 18 C atoms.

Particularly advantageous W/O emulsifiers are glyceryl monostearate,glyceryl monoisostearate, glyceryl monomyristate, glyceryl monooleate,diglyceryl monostearate, diglyceryl monoisostearate, propylene glycolmonostearate, propylene glycol monoisostearate, propylene glycolmonocaprylate, propylene glycol monolaurate, sorbitan monoisostearate,sorbitan monolaurate, sorbitan monocaprylate, sorbitan monoisooleate,sucrose distearate, cetyl alcohol, stearyl alcohol, arachidyl alcohol,behenyl alcohol, isobehenyl alcohol, selachyl alcohol, chimyl alcohol,polyethylene glycol(2) stearyl ether (Steareth-2), glyceryl monolaurate,glyceryl monocaprinate, glyceryl monocaprylate.

The invention will be explained in more detail below on the basis ofexamples, with reference to the appended figure:

EXAMPLE 1 Testing of Adequate Preservation by Synergistically Active1,2-diol-mixtures

A test for adequate preservation was carried out in accordance with theEuropean Pharmacopea.

The test thus consists of the contamination of the formulation, ifpossible in its final ratio, with a prescribed inoculum of suitablemicroorganisms, storage of the inoculated formulation at a specifictemperature, taking of samples from the vessel at specific intervals anddetermination of the number of microorganisms in the samples taken inthis way. The preserving properties are adequate if, under theconditions of the test, there is a distinct reduction or optionally noincrease in the germ count in the inoculated formulations after theprescribed times at the prescribed temperatures. Experimental details ofthe test procedure are described in the European Pharmacopea (ISBN3-7692-2768-9; 2001 supplement to the 3rd Edition, page 421-422, chapter5.1.3).

Test Germs:

The following microorganism strains were used for the tests for adequatepreservation:

A: Escherichia coli ATCC 8739

B: Pseudomonas aeruginosa ATCC 9027

C: Staphylococcus aureus ATCC 6538

D: Candida albicans ATCC 10231

E: Aspergillus niger ATCC 16404

The initial germ count (CFU/g; “0” value) was in the range of 240,000 to300,000 in the various test series.

Formulation:

For the tests for adequate preservation, (a) potentially synergisticallyactive mixtures taken into account and (b), for comparison purposes, thecorresponding unmixed 1,2-diols were incorporated in O/W emulsions.

Table 2 shows, by way of example, the formulation for a mixtureaccording to the invention consisting of 1,2-hexanediol (2%) and1,2-octanediol (1%). The variation in the total concentration of1,2-diols or 1,2-diol mixtures in the O/W emulsions was compensated forby increasing or reducing the water content, so that otherwise identicalformulations always comprised 100 parts by weight in total.

TABLE 2 Example of a formulation for a O/W emulsion containing a 1,2-hexanediol (2%)/1,2-octanediol (1%) mixture Raw material (Tradenameindicated in some cases) Manufacturer % (m/m) Water, low-germ 76.1Citric acid, 10% 0.4 Dragophos S DRAGOCO 2 PCL Liquid DRAGOCO 3Isodragol DRAGOCO 7 Lanette 18 COGNIS 4.5 Dracorin GMS DRAGOCO 2 DowCorning 200 fluid Dow Corning 2 1,2-hexanediol 2 1,2-octanediol 1 Total100

Result:

The results of the preservative loading tests for the 1,2-diols and1,2-diol mixtures tested are given in Table 3. Surprisingly, it wasfound that 1,2-diol mixtures consisting of defined mass ratios of1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and/or 1,2-decanediolhave a far greater activity than the individual substances metered inthe same concentration. This is shown, in particular, in the residualgerm counts remaining after 28 days. Binary and ternary mixtures of1,2-hexanediol with 1,2-pentanediol and/or 1,2-octanediol proved to beparticularly effective here. In the case of all 5 test germs(Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus,Candida albicans and Aspergillus niger it was possible to reduce theconcentration of colony forming units (CFU) to the preferred target 0value within the chosen time period.

As can be seen from Table 3 and FIG. 1 (test for adequate preservationfor Aspergillus niger over a period of 28 days; logarithmic plot of thereduction in the germ count for 1,2-hexanediol (3% in O/W emulsion), for1,2-octanediol (3%) and for a 1,2-hexanediol/1,2-octanediol mixture(mass ratio 2:1; dosage likewise 3%), it was possible in the case ofAspergillus niger, a germ that is particularly problematical with regardto the preservation of industrial products, to reduce the germ count to0 within 28 days by using the mixtures according to the invention. Onthe other hand, the individual substances (1,2-pentanediol,1,2-hexanediol, 1,2-octanediol and 1,2-decanediol; Table 3) tested forcomparison purposes, likewise in a dosage of 3%, did not enable areduction in the number of colony forming units (CFU) to the desired 0value in the case of Aspergillus niger. The test series (FIG. 1 and Tab.3) thus show, by way of example, that 1,2-diol mixtures consisting of atleast two different members of the group that consists of1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and 1,2-decanediol havea synergistically intensified activity.

Based on the available data, the synergistic intensification of theactivity of the diol mixtures according to the invention can also bedemonstrated on the basis of the Kull equation (F. C. Kull et al.;Applied Microbiology Vol. 9, p. 538-541 (1961); David C. Steinberg;Cosmetics & Toiletries Vol. 115 (No. 11), p. 59-62; November 2000; seealso Table 4 for the method of calculation). The Kull equation enablesthe pure substances and the active compound mixtures prepared therefromto be compared in respect of their antimicrobial activity. With thisequation the so-called synergy index (SI), which is a measure for asynergistic activity, but also for a possible antagonistic activity, ofa mixture having an antimicrobial action, is determined. A synergisticeffect is evident if the SI value determined is less than 1. On theother hand, if an SI of precisely 1 is calculated, there is a pureadditive effect of two substances having an antimicrobial action. In thecase of an SI value greater than 1, on the other hand, there is a(frequently undesired) antagonistic effect.

By way of example the calculation of the SI value for the treatment ofAspergillus niger with a mixture of 1,2-hexanediol and 1,2-octanediol(ratio 2:1) after an incubation phase of 14 days is shown below (Table4). The calculated SI of 0.106 clearly shows that a 2:1 mixture of1,2-hexanediol and 1,2-octanediol is a highly synergistic combination ofactive compounds. It was not possible to determine the 28-day SI valuesince after this incubation phase the germ counts were 0 when the diolmixture was used (cf. Table 3). The Kull equation cannot be used in thisparticular case; however, the synergy is, of course, in any eventevident on the basis of the germ count of 0.

TABLE 4 Calculation of the synergy index (SI) for 1,2-hexanediol/1,2-octanediol (Mass ratio: 2:1; dosage in O/W emulsion: 3%; test germ:Aspergillus niger) C 1,2- A B hexanediol + 1,2- 1,2- 1,2- octanediol;hexanediol octanediol Mass ratio: 2:1 Aspergillus niger: 28000 1000 30014 days [CFU/ml] Kull Equation: SI = C × D/A + C × E/B A: Germ count for28000 substance A B: Germ count for 1000 substance B C: Germ count for300 mixture of A + B D: Amount of A in C 0.66 E: Amount of B in C 0.33SI: Synergy Index 0.106 Literature: Synergy Index: D. C. Steinberg;Cosmetics & Toiletries 115 (11); p. 59-62 (2000) F. C. Kull et al.;Applied Microbiology 9; p. 538-541 (1961)

EXAMPLE 2 Determination of the Minimum Inhibitory Concentrations forVarious Germs and Calculation of Synergy Indices on the Basis of MICValues

Preliminary Remarks:

The finding that, in addition to their use as preservatives, the1,2-diol mixtures according to the invention are also suitable forcontrolling germs which, for example, are responsible for body odourgoes back to test series in which the particularly relevant germsStaphylococcus epidermidis, Corynebacterium xerosis and Brevibacteriumepidermidis were tested. In addition to the MIC values forStaphylococcus epidermidis, Corynebacterium xerosis and Brevibacteriumepidermidis, the corresponding synergy indices of the synergisticallyactive mixtures according to the invention were determined in these testseries (cf. Table 7).

In addition, the MIC determinations showed that the 1,2-diol mixturesclaimed also have a surprisingly good action against further test germssuch as Trichophyton mentagrophytes, Epidermophyton floccosum,Propionibacterium acnes, as a result of which the diol mixtures claimedcan also be used as agents against mycoses or acne.

An antagonistic effect was found only against Malassezia furfur.

General Test Conditions:

The antimicrobial action of 1,2-diols and of the dial mixtures accordingto the invention was demonstrated with the aid of the agar dilutionmethod based on DIN 58 940/ICS and DIN 58 944/ICS. Petri dishes 9.0 cmin diameter were charged with 13.5 ml freshly prepared Mueller-Hintonagar (Merck, Ref. 1.05437 or Wilkins-Chalgren agar boullion, Oxoid, Ref.CM 643, supplemented with log agar-agar/liter) kept liquid at 50° C., towhich the various concentrations of the diluted samples were added in10% (V/V)=1.5 ml. Mueller-Hinton agar that contained 3% Tween80 (Merck,Ref. 8.22 187) was used for the test germ Malassezia furfur.

In each case 5 ml of the samples were diluted in distilled water andmade up to 10 ml. The further test concentrations of the particulardilution series, which were prepared in the form of geometric series,were prepared by progressive 1:2 dilution of this batch with distilledwater.

By means of a further dilution with the test agar (1.5 ml sample orcorresponding dilutions+13.5 ml agar), 10 times lower finalconcentrations were achieved in each case (corresponds to an initialconcentration of 50,000 ppm in each case). Two agar plates were pouredper test concentration and nutrient medium.

The following controls were carried out, with two agar plates in eachcase:

K1: 15.0 ml Mueller-Hinton agar (not inoculated) K2: 13.5 mlMueller-Hinton agar + 1.5 ml distilled water (inoculated) K3: 13.5 mlMueller-Hinton agar + 1.5 ml distilled water (inoculated) K4: 15.0 mlMueller-Hinton agar (inoculated) K5: 15.0 ml Mueller-Hinton agar + 3%Tween 80 (not inoculated) K6: 13.5 ml Mueller-Hinton agar + 3% Tween80 + (not inoculated) 1.5 ml distilled water. K7: 13.5 ml Mueller-Hintonagar + 3% Tween 80 + (inoculated) 1.5 ml distilled water. K8: 15.0 mlMueller-Hinton agar + 3% Tween 80 (inoculated) K9: 15.0 mlWilkins-Chalgren agar (not inoculated) K10: 13.5 ml Wilkins-Chalgrenagar + 1.5 ml distilled (not inoculated) water K11: 13.5 mlWilkins-Chalgren agar + 1.5 ml distilled (inoculated) water K12: 15.0 mlWilkins-Chalgren agar + 1.5 ml distilled (inoculated) water

After solidification and drying (approx. 1 h at 37° C.), the test plateswere inoculated in point form with, in each case, 1 μl of the test germsuspensions listed below. To check purity and identity the bacteria thatgrow aerobically (Brevibacterium epidermidis, Corynebacterium xerosis,Staphylococcus epidermidis) were [lacuna] on Columbia blood agar(BioMérieux, Ref. 43049). The mould Aspergillus niger, the yeast Candidaalbicans and the two skin fungi Trichophyton mentagrophytes andEpidermophyton floccosum were cultured on Sabouraud agar (BioMérieux,Ref. 43555). Malassezia furfur was cultured on Sabourad HLT agar withdisinhibitors (addition of 3% Tween80: 1%; lecithin: 0.3%; histidine:0.1%; Merck, Ref. 1.18368). Propionibacterium acnes was cultured onSchaedler agar (BioMérieux, Ref. 43273). Further details on the testgerms can be taken from Table 5.

TABLE 5 Test germs (strain names) and germ counts Test germ Strain nameCFU*/ml Brevibacterium epidermidis ATCC 35514 2.8 × 10⁷ Corynebacteriumxerosis ATCC 7711 2.1 × 10⁷ Propionibacterium acnes ATCC 11829 2.0 × 10⁸Staphylococcus epidermidis ATCC 12228 2.2 × 10⁷ Malassezia furfur DSM6171 3.0 × 10⁷ Epidermophyton floccosum CBS 55384 2.1 × 10⁷ Trichophytonmentagrophtes CBS 26379 3.3 × 10⁷ CFU* = colony-forming units

The preparation of the test germ suspensions of the bacterial germs thatgrow aerobically was carried out by incubation of Mueller-Hinton broth(Merck, Ref. 1.10293) which had been inoculated with a few individualcolonies of the relevant test germs, at 36° C. After a distinctturbidity had been obtained, sterile nutrient broth was added to thesuspensions in such an amount that the turbidity thereof corresponded toMcFarland standard 0.5 (approx. 1.5×10⁸ CFU/ml).

For preparation of the other test germ suspensions, the test strainswere cultured on the abovementioned solid nutrient medium, harvestedusing sterile swabs and taken up or diluted in such an amount ofMueller-Hinton broth that the turbidity of the suspensions correspondedto McFarland standard 0.5.

All test germ suspensions with the exception of Propionibacterium acneswere diluted again 1:10 with sterile broth and the germ count thereofwas determined by the surface method using a Spiralometer (results: seeTable 5).

The inoculated plates were incubated under the conditions indicated inTable 6 and then evaluated. The MIC (minimum inhibitory concentration)was regarded as the lowest concentration of active compound at whichmacroscopically there is no growth. Minimal, barely visible growth orfew small individual colonies were evaluated as inhibition.

TABLE 6 Inoculation and Incubation Growth Test germ Strain nameconditions Nutrient medium Incubation Brevibacterium epidermidis ATCC35514 Aerobic Mueller-Hinton agar 18 h at 36° C. Corynebacterium xerosisATCC 7711 Aerobic Mueller-Hinton agar 18 h at 36° C. Propionibacteriumacnes ATCC 11829 Anaerobic Wilkins-Chalgren agar 72 h at 30° C.Staphylococus epidermidis ATCC 12228 Aerobic Mueller-Hinton agar 18 h at36° C. Malassezia furfur DSM 6171 Aerobic Mueller-Hinton agar + 3% 72 hat 30° C. Tween 80 Trichophyton CBS 26379 Aerobic Mueller-Hinton agar 72h at 30° C. mentagrophytes Epidermophyton CBS 55384 AerobicMueller-Hinton agar 18 h at 36° C. Floccosum

MIC Values for 1,2-hexanediol, 1,2-octanediol and a Mixture of the TwoDiols in a C6/C8 ratio=2:1

The MIC values for 1,2-hexanediol, 1,2-octanediol and for a mixture ofthe two diols in a mass ratio of 2 parts of hexanediol to 1 part ofoctanediol were determined in accordance with the general testconditions described (cf. Table 7).

TABLE 7 MIC values [ppm] for 1,2-hexanediol, 1,2-octanediol and for aC6/C8 diol mixture (2:1) Determination of the Synergy Indices (SI) inaccordance with the Kull et al^(1,2) equation Microorganism Strain No.MIC C6 MIC C8 MIC C6/C8 2:1 SI: C6/C8; 2:1 Staphylococcus ATCC 1222825000 12500 6250 0.55 epidermidis Corynebacterium ATCC 7711 12500 62506250 0.66 xerosis Brevibacterium ATCC 35514 25000 3125 6250 0.83epidermidis Propionibacterium ATCC 11829 25000 6250 3125 0.25 acnesMalassezia furfur DSM 6171 12500 50000 50000 2.97 Trichophyton CBS 263796300 1562 1562 0.49 mentagrophytes Epidermophyton CBS 55384 6250 31251562 0.32 floccosum ¹F. C. Kull et al.; Applied Microbiology 9; p.538–541 (1961) ²D. C. Steinberg; Cosmetics & Toiletries 115 (11); p.59–62 (2000)

The results shown in Table 7 show, for 1,2-hexanediol and 1,2-octanediolby way of example, the synergistic intensification of the activity ofthe 2:1 mixture of the two diols. Accordingly, microorganisms such asStaphylococcus epidermidis, Brevibacterium epidermidis, Corynebacteriumxerosis, Propionibacterium acnes, Trichophyton mentagrophytes andEpidermophyton floccosum are also clearly more strongly inhibited by the1,2-diol mixture in direct comparison with the corresponding individualsubstances. The synergy indices determined on the basis of the MICvalues with the aid of the Kull equation are also shown in Table 7. TheSI values clearly show that the 1,2-hexanediol/1,2-octanediol diolmixture has a synergistically intensified activity and, in addition toits excellent activity as a preservative (cf. Example 1) can alsopreferentially be used for controlling body odour (SI Staphylococcusepidermidis: 0.55; SI Corynebacterium xerosis: 0.66; SI Brevibacteriumepidermidis: 0.83), for controlling acne (SI Propionibacterium acnes:0.25) and for controlling the skin and nail mycoses caused byTrichophyton and Epidermophyton species (SI Trichophyton mentagrophytes:0.49; SI Epidermophyton floccosum: 0.32). On the other hand, in the caseof Malassezia furfur it was not possible to demonstrate a synergisticeffect for the 1,2-hexanediol/1,2-octanediol mixture (SI Malasseziafurfur: 2.97, i.e. antagonistic effect).

EXAMPLE 3 Testing of Adequate Preservation by Mixtures of (a)Synergistic Mixtures of 1,2-alkanediols with (b) Further Preservatives

Testing for adequate preservation by mixtures of (a) synergisticmixtures of 1,2-alkanediols with (b) further preservatives was likewisecarried out in accordance with the European pharmacopoeia. The testprocedure is described in detail in Example 1.

Test Germs:

The following microorganism strains were used for the tests for adequatepreservation:

A: Escherichia coli ATCC 8739

B: Pseudomonas aeruginosa ATCC 9027

C: Staphylococcus aureus ATCC 6538

D: Candida albicans ATCC 10231

E: Aspergillus niger ATCC 16404

The initial germ count (CFU/g; “0” value”) was in the range of 280,000to 320,000 in the various test series.

Formulation

For the tests for adequate preservation the potentially synergisticcombinations of active compounds taken into consideration, consisting of(a) the 1,2-diol mixtures according to the invention and (b) furtherpreservatives, were incorporated in emulsions in a defined amount. Forcomparison purposes the corresponding 1,2-diol mixtures according to theinvention and the further preservatives tested were incorporatedseparately into the same O/W emulsions.

Table 8 shows, by way of example, the formulation for a mixtureaccording to the invention consisting of 0.05% Euxyl K400 (mixture of1,2-dibromo-2,4-dicyanobutane (20%) and 2-phenoxyethanol (80%)), 0.25%1,2-hexanediol and 0.25% 1,2-octanediol. The variation in the totalconcentration of 1,2-diol mixture and additional preservative Euxyl K400in the O/W emulsions was compensated for by increasing or lowering thewater content, so that otherwise identical formulations always comprised100 parts by weight in total.

TABLE 8 Illustrative formulations for O/W emulsion containing A) 0.1%Euxyl K 400, B) 1% of a 1,2-diol mixture made up of 0.5% 1,2-hexanedioland 0.5% 1,2- octanediol and C) a combination of active compoundsconsisting of 0.05% Euxyl K 400, 0.25% 1,2-hexanediol and 0.25%1,2-octanediol. Raw material % (m/m) C (Tradename B 0.05% Euxyl K400indicated in A 0.5% hexanediol 0.25% hexanediol some cases) Manufacturer0.1% Euxyl K400 0.5% octanediol 0.25% octanediol Octanediol DRAGOCO 00.5 0.25 Hexanediol DRAGOCO 0 0.5 0.25 Euxyl K 400 Schülke/Mayr 0.1 00.05 K sorbate Ringe + Kuhlmann 0 0 0 Phenoxyethanol 0 0 0 Parabenmixture 0 0 0 Water, low germ 79.25 78.35 78.75 Citric acid, 10% 0.150.15 0.2 Dragophos S DRAGOCO 2 2 2 PCL Liquid DRAGOCO 3 3 3 IsodragolDRAGOCO 7 7 7 Lanette 18 COGNIS 4.5 4.5 4.5 Dracorin GMS 2/008474 2 2 2Dow Corning 200 fl. Dow Corning 2 2 2 Total 100 100 100

Result:

The results of the preservative loading tests for the combinations ofactive compounds tested, consisting of a synergistic mixture of1,2-alkanediols according to the invention and a further preservative,are given in Tables 9 and 10 for the system1,2-hexanediol/1,2-octanediol//Euxyl K400 by way of example.Surprisingly, it was found that not only 1,2-diol mixtures themselvesbut also combinations of 1,2-diol mixtures with further preservativesare able to achieve a significant synergistic intensification ofactivity compared with the individual substances metered in the sameconcentration. In the example mentioned, this is shown in particular inthe residual germ counts for Aspergillus niger remaining after 28 days.As can be seen from Table 9, in the case of Aspergillus niger, a germthat is particularly problematical with regard to the preservation ofindustrial products, it was possible to reduce the germ count to 2,800within 28 days by using formulation C. On the other hand, the diolmixture according to formulation B (1,2-hexanediol+1,2-octanediol; massratio 1:1) tested in a dosage of 1% and formulation A (containing EuxylK400), which was also tested in a concentration of 0.1% for comparisonpurposes, did not enable such a significant reduction in the number ofcolony forming units (CFU) in the case of Aspergillus niger. The testseries (Tab. 9) thus shows, by way of example, that mixtures of activecompounds consisting of (a) at least two different members of the groupthat consists of 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and1,2-decanediol and (b) a further preservative can possess a synergistic,further improved action.

TABLE 9 Testing for adequate preservation for a combination of activecompounds consisting of a synergistically active diol mixture accordingto the invention (1,2-hexanediol and 1,2- octanediol) and a furtherpreservative Euxyl K400; [CFU/ml] Esche- Pseudo- Asper- richia monasStaphylococcus Candida gillus Days Coli aeruginosa Aureus albicansniger 1. O/W emulsion with formulation A (0.1% Euxyl K400) 0 300,000320,000 310,000 310,000 280,000 1 200 0 0 <100 220,000 2 <100 0 0 <100140,000 4 0 0 0 0 120,000 7 0 0 0 0 200,000 14 0 0 0 0 160,000 28 0 0 00 32,000 2. O/W emulsion with formulation B (0.5% hexanediol + 0.5%octanediol) 0 300,000 320,000 310,000 310,000 280,000 1 0 0 0 3,200180,000 2 0 0 0 200 160,000 4 0 0 0 100 140,000 7 0 0 0 0 180,000 14 0 00 0 120,000 28 0 0 0 0 60,000 3. O/W emulsion with formulation C (0.25%hexanediol + 0.25% Octanediol + 0.05% Euxyl K 400) 0 300,000 320,000310,000 310,000 280,000 1 <100 <100 <100 <100 20,000 2 0 0 0 0 12,000 40 0 0 0 10,000 7 0 0 0 0 8,000 14 0 0 0 0 8,000 28 0 0 0 0 2,800

Based on the available data, the synergistic intensification of theactivity of the combination of active compounds consisting of (a) asynergistically active mixture of 1,2-alkanediols according to theinvention (for example 1,2-hexanediol and 1,2-octanediol) and (b) afurther preservative (for example Euxyl K400) can also be demonstratedon the basis of the Kull equation (F. C. Kull et al.; AppliedMicrobiology Vol. 9, p. 538-541 (1961); David C. Steinberg; Cosmetics &Toiletries Vol. 115 (No. 11), p. 59-62; November 2000; see also Table 10for the method of calculation). The Kull equation enables the puresubstances and the active compound mixtures prepared therefrom to becompared in respect of their antimicrobial activity. With this equationthe so-called synergy index (SI), which is a measure for a synergisticactivity, but also for a possible antagonistic activity, of a mixturehaving an antimicrobial action, is determined. A synergistic effect isevident if the SI value determined is less than 1. On the other hand, ifan SI of precisely 1 is calculated, there is a pure additive effect oftwo substances having an antimicrobial action. In the case of an SIvalue greater than 1, on the other hand, there is a (frequentlyundesired) antagonistic effect.

By way of example the calculation of the SI value for the treatment ofAspergillus niger with a mixture consisting of 1,2-hexanediol,1,2-octanediol and Euxyl K400 (formulation C) after an incubation phaseof 28 days is shown below. The calculated SI of 0.066 clearly shows thatthe mixture consisting of 1,2-hexanediol, 1,2-octanediol and Euxyl K400is a highly synergistic combination of active compounds.

TABLE 10 Calculation of the synergy index (SI) of a 1,2-hexanediol/1,2-octanediol/Euxyl K400 mixture (Formulation C) consisting of equalparts of the comparison 1,2-alkanediol mixture (Formulation A) and ofthe comparison solution Euxyl K400 (Formulation B) (mass ratio 1:1.;dosage in O/W emulsion: test germ: Aspergillus niger) C A 1,2-hexanediol1,2-hexanediol (0.25%) + 1,2- 0.5% + 1,2- B octanediol (0.25) +octanediol Euxyl K400 EuxylK400 0.5% 0.1% (0.05%); Aspergillus niger:60000 32000 2800 28 days [CFU/ml] Kull equation: SI = C × D/A + C × E/BA: Germ count 60000 for substance A B: Germ count for 32000 substance BC: Germ count for 2800 mixture of A + B D: Amount of A in 0.5 C E:Amount of B in 0.5 C SI: Synergy Index 0.066 Literature: Synergy Index:D. C. Steinberg; Cosmetics & Toiletries 115 (11); p. 59-62 (2000) F. C.Kull et al.; Applied Microbiology 9; p. 538-541 (1961)

TABLE 3 Testing for adequate preservation for 1,2-diols and 1,2 [lacuna]diol mixtures [CFU/ml] SL 231001 231001 231001 010801 050601 231001231001 231001 PE3 HE3 OC3 DE3 DEH HE/OC HE/OC/PE HE/OC/DE Code PE1HE1OC1HE1OC1DE1 Pentanediol Hexanediol PE2DE1 HE2/OC1 1% 1% PentanediolHexanediol Hexanediol Octanediol PE3 HE3 OC3 DE 3 2% 2% 1% 1%Pentanediol Hexanediol Octanediol Decanediol Decanediol OctanediolOctanediol Decanediol 3% 3% 3% 3% 1% 1% 1% 1% E. coli 0′-count 300,000300,000 300,000 350,00 290,000 300,000 300,000 300,000 24 h 300,000 <1000 0 0 0 0 0 48 h 145,000 <100 0 0 0 0 0 0  4 d 100,000 0 0 0 0 0 0 0  7d 40,000 0 0 0 0 0 0 0 14 d 500 0 0 0 0 0 0 0 28 d 0 0 0 0 0 0 0 0 Ps.aeruginosa 0′-count 290,000 290,000 290,000 360,000 270,000 290,000290,000 290,000 24 h 145,000 <100 0 2,600 0 0 0 0 48 h 12,000 <100 0 1.0 mill. 0 0 0 0  4 d 0 0 0 17.2 mill. 0 0 0 0  7 d 0 0 0 20.0 mill 00 0 0 14 d 0 0 0 15.0 mill 0 0 0 0 28 d 0 0 0 11.8 mill 0 0 0 0 Staph.aureus 0′-count 240,000 240,000 240,000 350,000 250,000 240,000 240,000240,000 24 h 100,000 <100 0 3,200 100 0 0 0 48 h 12,000 <100 0 0 0 0 0 0 7 d 0 0 0 0 0 0 0 0 14 d 0 0 0 0 0 0 0 0 28 d 0 0 0 0 0 0 0 0 C.albicans 0′-count 250,000 250,000 250,000 320,000 300,000 250,000250,000 250,000 24 h 245,000 120,000 3,200 3,500 54,000 1,700 1,80012,000 48 h 73,000 5,600 <100 0 400 0 0 <100  4 d 28,000 0 0 0 0 0 0 0 7 d 23,000 0 0 0 0 0 0 0 14 d <100 0 0 0 0 0 0 0 28 d 0 0 0 0 0 0 0 0A. niger 0′-count 260,000 260,000 260,000 250,000 250,000 260,000260,000 260,000 24 h 180,000 120,000 55,000 73,000 180,000 12,000 30,000180,000 48 h 180,000 120,000 6,000 160,000 82,000 10,000 18,000 160,000 4 d 180,000 120,000 6,000 100,000 64,000 8,000 16,000 140,000  7 d140,000 80,000 1,100 100,000 20,000 600 16,000 20,000 14 d 140,00028,000 1,000 73,000 12,000 300 600 6,000 28 d 100,000 800 100 73,0005,200 0 0 1,000

1. An antimicrobial composition, comprising an antimicrobial effectiveamount of a mixture of 1,2-alkanediols consisting of two or morestraight chain 1,2-alkanediols having chain lengths that (i) aredifferent and (ii) in each case are in the range of 5 to 10 C atoms,wherein said mixture of 1,2-alkanediols exhibits an antimicrobial effectcharacterized by a Kull value of less than
 1. 2. The antimicrobialcomposition according to claim 1, wherein the proportions of the saiddiols in the mixture are set such that a Kull value of 0.83 or less forthe antimicrobial effect exhibited by said mixture of 1,2-alkanediolsresults.
 3. The antimicrobial composition according to claim 1, whereinthe mixture contains 1,2-hexanediol and one, two or three furtherstraight-chain 1,2-alkanediols, the chain length of which in each caseis in the range of 5 to 10 C atoms.
 4. An antimicrobial compositioncomprising an antimicrobial effective amount of a mixture of1,2-alkanediols consisting of at least one of: (a) 1,2-hexanediol and1,2-octanediol, (b) 1,2-hexanediol and 1,2-decanediol, (c)1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol, (d) 1,2-hexanediol,1,2-octanediol and 1,2-decanediol and (e) 1,2-pentanediol,1,2-hexanediol and 1,2-decanediol as antimicrobial active compounds, theproportions of the said diols in the mixture of 1,2-alkanediols beingset such that a Kull value of less than 1.0 for the antimicrobial effectexhibited by said mixture of 1,2-alkanediols results.
 5. Theantimicrobial composition according to claim 1, wherein the proportionof each individual diol is in the range of 20 to 80% (m/m) based on thetotal mass of the mixture of the diols.
 6. An antimicrobial compositioncomprising an antimicrobial effective amount of a mixture of1,2-alkanediols consisting of two or more straight chain 1,2-alkanediolshaving chain lengths of which (i) are different and (ii) are in therange of 5 to 10 C atoms, wherein the proportions of said diols in themixture of 1,2-alkanediols are set such that a Kull value of less than1.0 for the antimicrobial effect exhibited by said mixture of1,2-alkanediols results for at least one of: (a) a cosmetic treatment ofmicroorganisms causing body odour, (b) a cosmetic treatment ofmicroorganisms causing acne, (c) a cosmetic treatment of microorganismscausing mycoses, (d) a treatment of microorganisms on or in inanimatematerial and (e) preservation of a perishable product.
 7. Anantimicrobially active pharmaceutical composition consisting of anantimicrobial effective amount of a mixture of 1,2-alkanediolsconsisting of two or more straight chain 1,2-alkanediols having chainlengths of which (i) are different and (ii) are in the range of 5 to 10C atoms, wherein the proportions of the said diols in the mixture of1,2-alkanediols are such that said mixture of 1,2 alkanediols exhibitsan antimicrobial effect characterized by a Kull value of less than 1.0.8. An antimicrobial composition according to claim 1, further comprisingan antimicrobial active compound in an amount at which an antimicrobialaction of a mixture of said antimicrobial active compound and saidmixture of 1,2-alkanediols is synergistically intensified, the furtherantimicrobial active compound not being a straight-chain 1,2-alkanediol.9. An antimicrobial composition, comprising: (a) as antimicrobial activecompound, a mixture of two, three or more straight-chain1,2-alkanediols, the chain lengths of which (i) are different and (ii)in each case are in the range of 5 to 10 C atoms, and (b) an excipientcompatible with the said mixture, wherein the proportions of the saiddiols in the mixture are set such that a Kull value of less than 1.0 forthe antimicrobial effect exhibited by said mixture of 1,2-alkanediolsresults.
 10. An antimicrobial composition, comprising (a) anantimicrobial effective amount of a mixture of two, three or morestraight-chain 1,2-alkanediols, the chain lengths of which (i) aredifferent and (ii) in each case are in the range of 5 to 10 C atoms, and(b) a preservative other than straight-chain 1,2-alkanediols, whereinthe proportions of the said diols in the mixture are set such that aKull value of less than 1.0 for the antimicrobial effect exhibited bysaid mixture of 1,2-alkanediols results.
 11. An antimicrobialcomposition as in claim 10, wherein said preservative (b) is selectedfrom the group consisting of benzoic acid and the esters and saltsthereof, propionic acid and salts thereof, salicylic acid and saltsthereof, 2,4-hexanoic acid and salts thereof, formaldehyde andparaformaldehyde, 2-hydroxybiphenyl ether and salts thereof,2-zincsulphidopyridine-N-oxide, inorganic sulphites and bisulphites,sodium iodate, chlorobutanolum,4-ethylmercury-(I1)-5-amino-1,3-bis(2-hydroxy)benzoic acid and salts andesters thereof, dehydraccetic acid, formic acid,1,6-bis(4-amidino-2-bromophenoxy)-n-hexane and salts thereof, the sodiumsalt of ethylmercury-(II)-thiosalicylic acid, phenylmercury and saltsthereof, 10-undecylenic acid and salts thereof,5-amino-1,3-bis(2-ethylhexyl)-5-methyl-hexahydropyrimidine,5-bromo-5-nitro-1,3-dioxane, 2-bromo-2-nitro-1,3-propanediol,2,4-dichlorobenzyl alcohol,N-(4-chlorophenyl)-N′-(3,4-dichlorophenyl)-urea, 4-chloro-m-cresol,2,4,4′-trichloro-2′-hydroxy-diphenyl ether, 4-chloro-3,5-dimethylphenol,1,1′-methylene-bis(3-(1-hydroxymethyl-2,4-dioximidazolidin-5-yl)urea),poly-(hexamethylene diguanide) hydrochloride, 2-phenoxyethanol,hexamethylentetramine, 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantanechloride, 1(4-chlorphenoxy)-1(1H-imidazol-1-yl)-3,3-dimethyl-2-butanone,1,3-bis-(hydroxy-methyl)-5,5-dimethyl-2,4-imidazolidinedione, benzylalcohol, octopirox, 1,2-dibromo-2,4-dicyanobutane,2,2′-methylene-bis(6-bromo-4-chloro-phenol), bromo-chlorophene, mixtureof 5-chloro-2-methyl-3(2H)isothiazolinone and2-methyl-3(2H)isothiazolinone with magnesium chloride and magnesiumnitrate, 2-benzyl-4-chlorophenol, 2-chloracetamide, chlorhexidine,chlorhexidine acetate, chlorhexidine gluconate, chlorhexidinehydrochloride, 1-phenoxy-propan-2-ol, N-alkyl(C₁₂-C₂₂)trimethyl-ammoniumbromide and chloride, 4,4-dimethyl-1,3-oxazolidine,N-hydroxymethyl-N-(1,3-di(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl)-N′-hydroxy-methylurea, 1,6-bis(4-amidino-phenoxy)-n-hexane and salts thereof,glutaraldehyde 5-ethyl-1-aza-3,7-dioxabicyclo(3.3.0)octane,3-(4-chlorphenoxy)-1,2-propanediol, hyamine,alkyl-(C₈-C₁₈)-dimethyl-benzylammonium chloride,alkyl-(C₈-C₁₈)-dimethyl-benzyl ammonium bromide,alkyl-(C₈-C₁₈)-dimethyl-benzyl ammonium saccharinate, benzylbemiformal,3-iodo-2-propinylbutyl carbamate, sodium hydroxymethyl-aminoacetate orsodium hydroxymethyl-aminoacetate.
 12. An antimicrobial composition asin claim 11, wherein said preservative (b) is1,2-dibromo-2,4-dicyanobutane.
 13. An antimicrobial composition as inclaim 11, wherein said preservative (b) is 2-phenoxyethanol.
 14. Anantimicrobial composition as in claim 10, wherein said preservative (b)is 3-iodo-2-propinyl-butyl carbamate.
 15. An antimicrobial compositionas in claim 11, wherein said mixture (a) comprises 1,2-hexanediol or1,2-octanediol.
 16. An antimicrobial composition as in claim 10, whereinsaid mixture of straight-chain 1,2-alkanediols comprises 1,2-hexanedioland 1,2-octanediol.
 17. An antimicrobial composition as in claim 10,further comprising a preservative.
 18. An antimicrobial composition asin claim 17, wherein said preservative is 3-iodo-2-propinyl-butylcarbamate.
 19. An antimicrobial composition as in claim 4, wherein said1,2-hexanediol and 1,2-octanediol are present in a ratio of 1:1.
 20. Anantimicrobial composition as in claim 4, wherein said 1,2-hexanediol and1,2-octanediol are present in a ratio of 2:1.
 21. The antimicrobialcomposition of claim 1, wherein said antimicrobial composition comprisessaid mixture of 1,2-alkanediols in an amount between 0.01 and 30% (m/m)by mass of said antimicrobial composition.
 22. The antimicrobialcomposition of claim 1, wherein said antimicrobial composition comprisessaid mixture of 1,2-alkanediols in an amount between 0.1 and 5% (m/m) bymass of said antimicrobial composition.